A known fastening apparatus for applying a self-piercing rivet include a nose assembly into which the rivet is passed from a rivet storage location, and from which the rivet is inserted into a workpiece by a punch. The fastening apparatus includes an upsetting die which is located beneath the workpiece and which is configured to upset the rivet when the rivet is inserted into the workpiece. Typically the volume and shape of the upsetting die is chosen to provide a desired degree of upsetting such that the rivet adopts a desired shape when it is inserted into the workpiece. However, for a workpiece having a lower sheet of formed of a cast material, high concentrated stress on the lower sheet during fastening can result in the lower sheet cracking.